Assessment of the Nutritional Value of Traditional Vegetables from Southern Chile as Potential Sources of Natural Ingredients.

There is an increasing interest in consuming healthy foods motivated by the need of boosting the immune system naturally. In this sense, vegetables rich in bioactive compounds are a clear example of "superfoods" that promotes overall health and strengthen the immune response. Therefore, in this study eight traditional vegetables usually produced in southern Chile (pea, corn, carrot, leek, spinach, chard, coriander and parsley) were characterized in terms of their nutritional composition to evaluate their potential as lyophilized natural ingredients. Thus, chemical composition, amino acid profile, minerals, vitamins, carotenoids, polyphenols and pesticide residues were evaluated. Green leafy vegetables resulted to be an excellent source of proteins and dietary fibers as well as vitamins (ascorbic acid, choline, alpha-tocopherol and niacin), minerals (calcium, phosphorus and iron), carotenoids and polyphenols. Among the eight vegetables assessed spinach exhibited the more balanced nutritional profile. Moreover, 332 pesticide residues were analysed and only six were detected in a low concentration. Due to their nutritional properties, the present results suggest that vegetables produced in southern Chile could be considered as promising alternatives to develop natural food ingredients.

Synthesis of New Chitosan from an Endemic Chilean Crayfish Exoskeleton (Parastacus Pugnax): Physicochemical and Biological Properties.

Chitin is one of the most abundant natural polysaccharides in the world and it is mainly used to produce chitosan by a deacetylation process. In the present study, the extraction of chitin and chitosan from the Parastacus pugnax (P. pugnax) crayfish exoskeleton was studied for the first time. Thus, the P. pugnax crayfish exoskeleton was converted to chitosan following the steps of depigmentation, deproteinization, and deacetylation. The produced chitosan (Chitosan-CGNA) was characterized in terms of the protein content, solubility, degree of deacetylation, viscosity, molecular weight, FTIR, SEM, XRD, antimicrobial, and antioxidant activity. The results showed that the obtained chitosan had a high degree of deacetylation (91.55%) and a medium molecular weight (589.43 kDa). The antibacterial activity of the chitosan was tested against bacterial strains relevant for the food industry and the lowest minimum inhibitory concentration (MIC) values were evidenced with Salmonella tiphymurium (S. typhimurium), Staphylococcus aureus (S. aureus), Enterococcus faecalis (E. faecalis) and Listeria. Monocytogenes (L. monocytogenes). Moreover, the Chitosan-CGNA showed an effect on DPPH radical scavenging activity, and its antioxidant activity was dependent on concentration and deacetylation degree. These results suggest that P. pugnax exoskeleton could be an excellent natural source for the production of chitosan with potential applications in the health system, and to prevent infections associated with pathogens strains.

Chemical and Nutritional Evaluation of Protein-Rich Ingredients Obtained through a Technological Process from Yellow Lupin Seeds (Lupinus luteus).

In recent years, interest in plant-based proteins has been rising due to ethical and sustainability issues. In this context, the production of protein concentrates and isolates from new plant sources have increased enormously because of their nutritional and techno-functional properties. Therefore, this work describes a pilot process for obtaining protein-rich ingredients from a yellow lupin variety (Lupinus luteus) developed by the Agriaquaculture Nutritional Genomic Center (CGNA). A protein alkaline solubilisation followed by isoelectric precipitation was used as a method for obtaining a protein concentrate (LPC) and isolate (LPI) with 75 and 95% protein, respectively. The changes in the protein quality and chemical composition during the protein concentration process from lupin flour were evaluated. Thus, nutritional parameters such as the amino acids (AAs) profile, essential amino acid index (EAAI), chemical score (CS), the protein efficiency ratio (PER), and digestible indispensable amino acid score (DIAAS) were determined to evaluate the nutritional quality of LPC and LPI. The facile and scalable protein isolation method without a defatting process proposed in this study showed a great protein separation efficiency (PSE), while the amino acids profile was not affected during both the concentration as well as the isolation of proteins. In addition, SDS-PAGE showed that both LPC and LPI mainly contained the high-molecular-weight proteins α and ß-conglutins. Both LPC and LPI had a balanced amino acids profile, and arginine was the most predominant amino acid. These results are useful for increasing the use of lupin based-protein ingredients as a potential functional ingredient in the food industry.

Cationization of kappa- and iota-carrageenan--Characterization and properties of amphoteric polysaccharides.

Commercial kappa- and iota carrageenans were cationized with 3-chloro-2-hydroxypropyltrimethylammonium chloride in aqueous sodium hydroxide solution. For kappa-carrageenan three derivatives with different degrees of substitution were obtained. Native and amphoteric kappa-carrageenans were characterized by NMR and infrared spectroscopy, scanning electron and atomic force microscopy; methanolysis products were studied by electrospray ionization mass spectrometry. Young moduli and the strain at break of films, differential scanning calorimetry, rheological and flocculation behavior were also evaluated; the native and the amphoteric derivatives showed different and interesting properties. Cationization of iota-carrageenan was more difficult, indicating as it was previously observed for agarose, that substitution starts preferentially on the 2-position of 3,6-anhydrogalactose residues; in iota-carrageenan this latter unit is sulfated.

The effects of NO3(-) supply on Mazzaella laminarioides (Rhodophyta, Gigartinales) from southern Chile.

The effects of nitrate supply on growth, pigments, mycosporine-like amino acids (MAAs), C:N ratios and carrageenan yield were investigated in Mazzaella laminarioides cultivated under solar radiation. This species is economically important in southern Chile where an increase of nitrogen in coastal waters is expected as a consequence of salmon aquaculture activity. Apical segments were cultivated in enriched seawater with five different NO3(-) concentrations (0, 0.09, 0.18, 0.38 and 0.75 mm) during 18 days. Although phycoerythrin and phycocyanin content, as well as C:N ratios, were reduced in the control treatment (without NO3(-) supply), when compared to NO3(-) treatments, total MAA concentration, carrageenan yield and growth rates were similar in all tested conditions. Nevertheless, during the experiment, an important synthesis of mycosporine-glycine took place in a nitrate concentration-dependent manner, with accumulation being saturated around 0.18 mm of nitrate. These results indicate that exposure to high NO3(-) concentration of more than 100 times the values observed in the nature did not impair the photoprotection system, as determined by MAAs, nor did it have a deleterious effect on growth or carrageenan yield of M. laminarioides, a late successional species from Chile.

A sulfated galactan with antioxidant capacity from the green variant of tetrasporic Gigartina skottsbergii (Gigartinales, Rhodophyta).

The water soluble polysaccharide produced by the green variant of tetrasporic Gigartina skottsbergii was found to be composed of D-galactose and sulfate groups in a molar ratio of 1.0:0.65. (1)H and (13)C NMR spectroscopy studies of the desulfated polysaccharide showed a major backbone structure of alternating 3-linked ß-D-galactopyranosyl and 4-linked α-D-galactopyranosyl units, and minor signals ascribed to 3-O-methyl-substitution on the latter unit. Ethylation analysis of the polysaccharide indicated that the sulfate groups are mainly located at position O-2 of 4-linked α-D-galactopyranosyl residue and partially located at positions O-6 of the same unit and at position O-2 of 3-linked ß-D-galactopyranosyl residue, and confirmed the presence of 3-O-methyl-galactose in minor amounts (4.4%). The sulfated d-galactan presents a similar structure to λ carrageenan but with much lower sulfation at position O-6 of the α-residue and at position O-2 of ß-residue. The antioxidant capacity of the sulfated d-galactan was evaluated by the peroxyl radicals (ORAC method), hydroxyl radicals, chelating activity, and ABTS(+) assays. Kinetic results obtained in these assays were compared with those obtained for the commercial λ carrageenan. The antioxidant activity toward peroxyl radicals was higher for commercial λ carrageenan, this agrees with its higher content of sulfate group. The kinetics of the reaction of both polysaccharides with hydroxyl and ABTS(+) radicals showed a complex mechanism, but the antioxidant activity was higher for the polysaccharide from the green variant of tetrasporic Gigartina skottsbergii.